The invention relates to an arrangement for feeding transport containers of a sorting conveyor with flat mailed items, wherein the arrangement has a linear conveyor which engages one surface of the respective mailed items in a planar frictional lock for the transfer of the mailed items to the transport containers.
Arrangements of this type are used, for example, in post offices for sorting of letters according to their mailing addresses. For this purpose, the letters are fed to the feeding arrangement after their mailing addresses have been captured. After transfer to the transport containers, a sorting conveyor then transports the letters to collection points predetermined by the mailing addresses.
For this purpose, a feeding arrangement of the above-described type has been proposed which transfers flat mailed items deposited on a linear conveyor embodied as a conveyor belt extending downward at an angle to the transport containers circulating below the conveyor belt. The transport containers are embodied as transport pouches which can be opened and are secured to a conveyor chain. The planar frictional lock between the one surface of the mailed items and the conveyor belt, i.e., a frictional lock extending longitudinally as well as perpendicularly to the direction of conveyance, ensures that, during the transfer, the conveyor belt adequately carries along standard mailed items and that, thus, the transported items are transferred to the transport containers in a reliable manner. But during the transfer of light mailed items, such as letters, it is possible that the frictional lock between the mailed item and the conveyor belt is cancelled under the influence of turbulent air flows caused by the transport motion and that a disturbance of the transfer occurs.
To solve this problem, it has been proposed to provide the conveyor belt of the feeding arrangement with ribs between which windows are formed that serve to receive the mailed items. Even after a cancellation of the frictional lock, this arrangement can push the mailed items so that they are transferred in direction of conveyance rearward to the transport containers by means of the limiting rib of the respective window. To ensure a reliable transfer in this arrangement, it is necessary to use a guide wall which extends above and parallel to the conveyor belt. As a result, only a narrow lateral opening of a shaft formed between the conveyor belt, the ribs of the windows and the guide wall is available for the deposit of the mailed items on the conveyor belt. Therefore, malfunctions may easily removed when such an arrangement is used, for example, if the mailed items are not oriented precisely parallel to the conveyor belt when placed into the shaft.
European Patent Application EP-A-0 519 375 discloses a feeding arrangement for the transfer of flat mailed items to transport containers of a sorting conveyor wherein, for transfer to the transport containers, the mailed items are conveyed in a roll gap formed between a rotatable roller and a clamping roller. Here, the clamping roller is only applied to the mailed items after the mailed items have been deposited on a depositing surface through which the rotatable roller extends. This ensures a reliable transfer of the mailed items even when they are not oriented precisely parallel to the depositing surface. On the other hand, a large clamping force is necessary between the rotatable roller and the clamping roller for the conveyance of the mailed items in the roll gap. This may result in damage when delicate mailed items are transferred, for example, packages containing eyeglass lenses or the like.